dimanche 5 octobre 2008

Perseus 12

ε, Double, 3.5 and 9, greenish white and lilac.

In China this, with the 4th‑magnitude ν and some others, was Keuen She.It has been suspected of variation in color as well as in light. The components are about 9ʺ apart, at a position angle of 10°, and form an interesting object for a four-inch telescope.

η, Double, 5 and 8.5, orange and smalt blue,

is unnamed except in China, where, with γ, it was Tien Chuen, Heaven's Ship. But it is noticeable in having three small stars on one side nearly in line, and one on the other, forming a miniature representation of Jupiter and his satellites. The components are 28ʺ apart, at a position angle of 300°.λ and μ, 4th- to 5th‑magnitude stars, were Tseih Shwuy, Piled-up Waters.ξ, a 4 1/2‑magnitude, is the Menkib of Burritt, from Mankib al Thurayya, the Shoulder of — i.e. next to — the Pleiades in the Arabian figure, although on modern charts it marks the left ankle.π, a double star of 4th and 9th magnitudes, is Ati and Atik, from the word Al ʽĀtiḳ found on the Borgian globe, at the space between the shoulders, and applied to it by Ulug Beg; but it is now located near the left foot.π, a 4 1/2‑magnitude, was Gorgonea secunda; and ρ, a variable from 3.4 to 4.2, orange in color, was Gorgonea tertia.τ, a 4 1/2‑magnitude, with others in the constellation, was known by the Chinese as Ta Ling, the Great Mound.

υ, 3.8,

marking the tip of the weapon in Perseus' hand, bears many titles with Bayer, all referring to its location; but none of these — indeed, no name at all — is seen in modern lists. Bayer wrote of them:In falce adamanthinā trium praecedens. Falx dicitur & curvus Harpes, Gladius falcatus, & incurvus, Arab. Nembus, Maroni Ensis falcatus, & curvus Saturni dens.The "Arab." would seem erroneous, for Nembus is neither Arabic nor Latin, and if intended for Nimbus, is equally wrong, as there is no suspicion of nebulosity about the star. Curvus Saturni dens was Vergil's designation in the Georgics [II.406] for a "pruning-hook," and the equivalent of Falx and Ἅρπη, so well known in connection with Perseus.χ, a multiple star, and the little h mark two clusters noticeable with the naked eye, Nos. 884 and 869 of the New General Catalogue, 30ʹ and 15ʹ in diameter, almost connected, and apparently a protuberant part of the Milky Way. They were the Arabians' Miʽṣam al Thurayya, the Wrist of — i.e. next to — the Pleiades.Hipparchos seems to have been the first to record them, which he did as νεφελοειδής, a "cloudy spot"; Ptolemy, as συστροφή, a "dense mass"; and subsequent astronomers down to Galileo's day similarly considered them nebulous. The Alfonsine Tables said, revolutio nebulosa, and the Almagest of 1551, girus ille in capulo ensis, this girus — correctly gyrus — signifying a circle. They seem strangely to have escaped the notice of astrologers, p335who, as a rule, devoted much attention to clusters as harmful objects which portended accidents to sight and blindness.In China they were Foo Shay.These stars and clusters are now known as the Sword Hand of Perseus, i, g, φ, and υ marking the outstretched sword. In small telescopes the twin clusters form one of the most beautiful objects within their reach.Between χ and η lies the diverging point of the Perseids, the prominent meteor stream visible from the 19th of July to the 17th of August, its maximum occurring about the 10th of the latter month and continuing several days. These appear in the early part of the night, at an elevation of from fifty-six to seventy miles, moving with moderate speed and leaving streaks of yellow light; the radiant advancing nearly 30° eastward during their period of visibility. Schiaparelli found their orbit coincident with that of Tuttle's comet, III of 1862. The Perseids were recorded as far back as 811, seven appearances being mentioned down to 841, and they are supposed to have been members of the solar system for thousands of years, although now, perhaps, steadily decreasing in number. Dante may have made reference to them in the Purgatorio [V.37‑39]:Vapors enkindled saw I ne'er so swiftlyAt early nightfall cleave the air serene,Nor, at the set of sun, the clouds of August;and in the later Middle Ages they were known as the Larmes de Saint Laurent, - Not only in the faraway Middle Ages nor only in France! In Italy the lagrime di S. Lorenzo are still associated and celebrated with the saint's feast, as for example on the mountain of Ponze di Trevi in Umbria; an ideal place from which to see them, far from smog and light pollution. -Saint Laurence's - It is in the church of this Saint Laurence at Upton that the remains of Sir William Herschel lie buried, and over them is the fitting inscription:

Coelorum perrupit claustra. -

Tears, his martyrdom upon the red-hot gridiron having taken place on the 10th of August, 258.